/*
 * Copyright (c) 1982, 1986, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)ip.h        8.1 (Berkeley) 6/10/93
 * ip.h,v 1.3 1994/08/21 05:27:30 paul Exp
 */

#ifndef _IP_H_
#define _IP_H_

#ifdef HOST_WORDS_BIGENDIAN
# undef NTOHL
# undef NTOHS
# undef HTONL
# undef HTONS
# define NTOHL(d)
# define NTOHS(d)
# define HTONL(d)
# define HTONS(d)
#else
# ifndef NTOHL
#  define NTOHL(d) ((d) = ntohl((d)))
# endif
# ifndef NTOHS
#  define NTOHS(d) ((d) = ntohs((uint16_t)(d)))
# endif
# ifndef HTONL
#  define HTONL(d) ((d) = htonl((d)))
# endif
# ifndef HTONS
#  define HTONS(d) ((d) = htons((uint16_t)(d)))
# endif
#endif

typedef uint32_t n_long;                 /* long as received from the net */

#ifdef _MSC_VER
# define PACKED_BEGIN __pragma( pack(push, 1) )
# define PACKED_END __pragma( pack(pop) )
#else
# define PACKED_BEGIN
#if defined(_WIN32)
# define PACKED_END __attribute__((gcc_struct, packed))
#else
# define PACKED_END __attribute__((packed))
#endif
#endif

/*
 * Definitions for internet protocol version 4.
 * Per RFC 791, September 1981.
 */
#define IPVERSION       4

/*
 * Structure of an internet header, naked of options.
 */
PACKED_BEGIN
struct ip {
#ifdef HOST_WORDS_BIGENDIAN
        uint8_t ip_v:4,                 /* version */
                ip_hl:4;                /* header length */
#else
        uint8_t ip_hl:4,                /* header length */
                ip_v:4;                 /* version */
#endif
        uint8_t         ip_tos;                 /* type of service */
        uint16_t        ip_len;                 /* total length */
        uint16_t        ip_id;                  /* identification */
        uint16_t        ip_off;                 /* fragment offset field */
#define IP_DF 0x4000                    /* don't fragment flag */
#define IP_MF 0x2000                    /* more fragments flag */
#define IP_OFFMASK 0x1fff               /* mask for fragmenting bits */
        uint8_t ip_ttl;                 /* time to live */
        uint8_t ip_p;                   /* protocol */
        uint16_t        ip_sum;                 /* checksum */
        struct  in_addr ip_src,ip_dst;  /* source and dest address */
} PACKED_END;

#define IP_MAXPACKET    65535           /* maximum packet size */

/*
 * Definitions for IP type of service (ip_tos)
 */
#define IPTOS_LOWDELAY          0x10
#define IPTOS_THROUGHPUT        0x08
#define IPTOS_RELIABILITY       0x04

/*
 * Definitions for options.
 */
#define IPOPT_COPIED(o)         ((o)&0x80)
#define IPOPT_CLASS(o)          ((o)&0x60)
#define IPOPT_NUMBER(o)         ((o)&0x1f)

#define IPOPT_CONTROL           0x00
#define IPOPT_RESERVED1         0x20
#define IPOPT_DEBMEAS           0x40
#define IPOPT_RESERVED2         0x60

#define IPOPT_EOL               0               /* end of option list */
#define IPOPT_NOP               1               /* no operation */

#define IPOPT_RR                7               /* record packet route */
#define IPOPT_TS                68              /* timestamp */
#define IPOPT_SECURITY          130             /* provide s,c,h,tcc */
#define IPOPT_LSRR              131             /* loose source route */
#define IPOPT_SATID             136             /* satnet id */
#define IPOPT_SSRR              137             /* strict source route */

/*
 * Offsets to fields in options other than EOL and NOP.
 */
#define IPOPT_OPTVAL            0               /* option ID */
#define IPOPT_OLEN              1               /* option length */
#define IPOPT_OFFSET            2               /* offset within option */
#define IPOPT_MINOFF            4               /* min value of above */

/*
 * Time stamp option structure.
 */
PACKED_BEGIN
struct  ip_timestamp {
        uint8_t ipt_code;               /* IPOPT_TS */
        uint8_t ipt_len;                /* size of structure (variable) */
        uint8_t ipt_ptr;                /* index of current entry */
#ifdef HOST_WORDS_BIGENDIAN
        uint8_t ipt_oflw:4,             /* overflow counter */
                ipt_flg:4;              /* flags, see below */
#else
        uint8_t ipt_flg:4,              /* flags, see below */
                ipt_oflw:4;             /* overflow counter */
#endif
        union ipt_timestamp {
                n_long  ipt_time[1];
                struct  ipt_ta {
                        struct in_addr ipt_addr;
                        n_long ipt_time;
                } ipt_ta[1];
        } ipt_timestamp;
} PACKED_END;

/* flag bits for ipt_flg */
#define IPOPT_TS_TSONLY         0               /* timestamps only */
#define IPOPT_TS_TSANDADDR      1               /* timestamps and addresses */
#define IPOPT_TS_PRESPEC        3               /* specified modules only */

/* bits for security (not byte swapped) */
#define IPOPT_SECUR_UNCLASS     0x0000
#define IPOPT_SECUR_CONFID      0xf135
#define IPOPT_SECUR_EFTO        0x789a
#define IPOPT_SECUR_MMMM        0xbc4d
#define IPOPT_SECUR_RESTR       0xaf13
#define IPOPT_SECUR_SECRET      0xd788
#define IPOPT_SECUR_TOPSECRET   0x6bc5

/*
 * Internet implementation parameters.
 */
#define MAXTTL          255             /* maximum time to live (seconds) */
#define IPDEFTTL        64              /* default ttl, from RFC 1340 */
#define IPFRAGTTL       60              /* time to live for frags, slowhz */
#define IPTTLDEC        1               /* subtracted when forwarding */

#define IP_MSS          576             /* default maximum segment size */

PACKED_BEGIN
#if SIZEOF_CHAR_P == 4
struct mbuf_ptr {
        struct mbuf *mptr;
        uint32_t dummy;
} PACKED_END;
#else
struct mbuf_ptr {
        struct mbuf *mptr;
} PACKED_END;
#endif

struct qlink {
        void *next, *prev;
};

/*
 * Overlay for ip header used by other protocols (tcp, udp).
 */
PACKED_BEGIN
struct ipovly {
        struct mbuf_ptr ih_mbuf;        /* backpointer to mbuf */
        uint8_t ih_x1;                  /* (unused) */
        uint8_t ih_pr;                  /* protocol */
        uint16_t        ih_len;                 /* protocol length */
        struct  in_addr ih_src;         /* source internet address */
        struct  in_addr ih_dst;         /* destination internet address */
} PACKED_END;

/*
 * Ip reassembly queue structure.  Each fragment
 * being reassembled is attached to one of these structures.
 * They are timed out after ipq_ttl drops to 0, and may also
 * be reclaimed if memory becomes tight.
 * size 28 bytes
 */
PACKED_BEGIN
struct ipq {
        struct qlink frag_link;                 /* to ip headers of fragments */
        struct qlink ip_link;                           /* to other reass headers */
        uint8_t ipq_ttl;                /* time for reass q to live */
        uint8_t ipq_p;                  /* protocol of this fragment */
        uint16_t        ipq_id;                 /* sequence id for reassembly */
        struct  in_addr ipq_src,ipq_dst;
} PACKED_END;

/*
 * Ip header, when holding a fragment.
 *
 * Note: ipf_link must be at same offset as frag_link above
 */
PACKED_BEGIN
struct  ipasfrag {
        struct qlink ipf_link;
        struct ip ipf_ip;
} PACKED_END;

#define ipf_off      ipf_ip.ip_off
#define ipf_tos      ipf_ip.ip_tos
#define ipf_len      ipf_ip.ip_len
#define ipf_next     ipf_link.next
#define ipf_prev     ipf_link.prev

/*
 * Structure stored in mbuf in inpcb.ip_options
 * and passed to ip_output when ip options are in use.
 * The actual length of the options (including ipopt_dst)
 * is in m_len.
 */
#define MAX_IPOPTLEN    40

PACKED_BEGIN
struct ipoption {
        struct  in_addr ipopt_dst;      /* first-hop dst if source routed */
        int8_t  ipopt_list[MAX_IPOPTLEN];       /* options proper */
} PACKED_END;

#endif
